JP2019039143A - Light guide member and light guide structure - Google Patents

Abstract

To provide a light guide member and a light guide structure having high light guide performance and high soundproof performance.SOLUTION: The light guide member includes a sheet member having a plurality of through holes penetrating in the thickness direction, the average opening diameter of the through holes is 1 μm or more and 250 μm or less, and at least one surface of the sheet member is 50% or more in light reflectance in a visible light region, and both surfaces of the sheet member are in contact with the fluid in at least a part of the sheet member, and a peak value of a normal incidence sound absorption coefficient of the sheet member is 10% or more in an audible range.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light guide member and a light guide structure.

The light guide structure is installed, for example, as a light duct in a building such as an apartment and a house, and guides outside light indoors to brighten the room. The light guiding structure uses external light, and lighting can be performed without using a lighting device such as a fluorescent lamp, so that electricity and the like are unnecessary.
Moreover, the inside of the pet box can be brightened by using a light guiding structure for the ventilation duct of the pet box and the like.

  For example, in Patent Document 1, a light duct is attached to an outer wall of a building so as to cover a window of the building and introduces light from the window to a room of the building, and is more vertical than the window It is located on the upper side, the daylighting part to collect sunlight from the outside of the building, the mounting part attached to the outer wall, and the outside of the outer wall, and the gap distance between the outer wall goes upward in the vertical direction A wall which forms a space which is continuously or gradually increased, a first reflecting portion provided on the inner surface of the wall, and a second reflecting provided in the light duct and facing the first reflecting portion An optical duct is described which is configured to have a light source and to reflect sunlight emitted from the light receiving part by the first reflecting part and the second reflecting part and to guide the light to the window part.

JP, 2009-76212, A

The light guiding structure for guiding external light to the inside such as a light duct has both open end faces, one open end face is disposed outside the building, and the other open end face is disposed in the building Ru. Therefore, the sound passes through the inside of the light duct unobstructed, the outside sound is likely to leak in the building and the sound in the building to the outside, and the noise is likely to be a problem.
On the other hand, for example, by covering the opening end face with a transparent member, it is conceivable to make a structure in which light does not easily pass through. However, even when it is covered by a transparent member, there is a problem that the sound is more likely to be missed compared to the surrounding wall due to the vibration of the transparent member.
Moreover, regarding the structure used for passing air, such as a ventilation duct and an apartment sleeve, it was not able to cover with a transparent member, but it had a structure where a sound passes as it is.

Patent Document 1 describes that a porous sound absorber such as felt, urethane foam and glass wool is provided on a wall as a sound absorbing layer. However, in order to increase the sound absorption performance of such a general porous sound absorber, it is necessary to obtain sufficient sound absorption performance in a configuration in which the porous sound absorber is disposed in a part of the light duct, since a volume is required. I could not In addition, since the porous sound absorber does not easily transmit light, if the volume of the porous sound absorber is increased to obtain sufficient sound absorption performance, the light guiding performance is degraded.
Moreover, since many porous sound absorbers such as urethane are easily deteriorated by light and / or heat, the sound absorption performance is deteriorated by the deterioration with time. Furthermore, since the porous sound absorber is in the form of fibers, there is a problem that fiber dust is generated, and a large amount of dust enters the room.

  An object of the present invention is to solve the problems of the prior art and to provide a light guiding member and a light guiding structure having high light guiding performance and high soundproofing performance.

As a result of intensive studies to solve the above problems, the present inventors have provided a sheet member having a plurality of through holes penetrating in the thickness direction, and the average opening diameter of the through holes is 1 μm to 250 μm. At least one surface has a light reflectance of 50% or more in the visible light region, and both surfaces of at least a part of the sheet member are in contact with the fluid, and the peak value of the normal incidence sound absorption coefficient of the sheet member is 10% in the audible range By finding out that the above problems can be solved by the above, the present invention has been completed.
That is, it discovered that the said subject was solvable by the following structures.

[1] A sheet member having a plurality of through holes penetrating in the thickness direction,
The average opening diameter of the through holes is 1 μm or more and 250 μm or less,
At least one surface of the sheet member has a light reflectance of 50% or more in the visible light region,
Both sides of at least part of the seat member are in contact with the fluid,
A light guide member in which the peak value of the normal incidence sound absorption coefficient of the sheet member is 10% or more in the audible range.
[2] The light guide member according to [1], wherein the sheet member is formed in a tubular shape.
[3] The light guide member according to [1] or [2], wherein the average opening diameter of the through holes is 1 μm or more and less than 100 μm.
[4] Assuming that the average opening diameter of the through holes is phi (μm) and the thickness of the sheet member is t (μm), the average opening ratio rho of the through holes is in a range larger than 0 and smaller than 1 and rho_center A range having an upper limit of rho_center + (0.795 × (phi / 30) ⁻² ) with a lower limit of rho_center− (0.052 × (phi / 30) ⁻² ) centering on (2 + 0.25 × t) × phi ^−1.6 The light guide member according to [3].
[5] The light guide member according to any one of [1] to [4], wherein the average aperture ratio of the through holes is 20% or less.
[6] The light guide member according to any one of [1] to [5], wherein the sheet member is made of a material having heat resistance and flame resistance.
[7] The light guide member according to any one of [1] to [6], wherein the forming material of the sheet member is a metal.
[8] The light guide member according to [7], wherein the metal is aluminum.
[9] The light guide member according to any one of [1] to [8], in which the light reflectance of the sheet member varies depending on the wavelength in the visible light region.
[10] A light guide structure in which the light guide member according to any one of [1] to [9] is disposed in a tubular duct member.
[11] The light guide structure according to [10], wherein the light guide member is disposed parallel to the inner wall surface of the duct member.
[12] The light guide structure according to [11], including a partition member that divides the space between the light guide member and the inner wall surface of the duct member in the axial direction of the duct member.
[13] The light guide structure according to [12], having at least one cell having different sizes when each space partitioned by the partition member is a cell.
[14] The light guide structure according to [12] or [13], wherein the visible light transmittance of the partition member is 60% or more.
[15] The duct member has a bent portion,
The light guide structure according to any one of [10] to [14], wherein the light guide member is disposed at the bent portion.
[16] One end of the duct member is disposed on the outside of the building, and the other end of the duct member is disposed on the inside of the building,
The light guide structure according to any one of [10] to [15], which guides light from the outside of the building to the inside.
[17] The light guide structure according to any one of [10] to [16], wherein the duct member is at least one of an intake pipe and an exhaust pipe.

  According to the present invention, it is possible to provide a light guide member and a light guide structure having high light guide performance and high soundproof performance.

It is a perspective view which shows typically an example of the light guide structure of this invention. It is sectional drawing of a direction parallel to the central axis of the light guide structure shown in FIG. It is sectional drawing of the direction perpendicular | vertical to the central axis of the light guide structure shown in FIG. It is sectional drawing which shows typically the building in which the light guide structure was installed. It is sectional drawing which shows typically another example of the light guide structure of this invention. It is sectional drawing which shows typically another example of a light guide member. It is a top view which shows typically another example of a light guide member. It is a top view of the light guide member which the light guide structure of FIG. 1 has. It is a graph showing the relation between distance and eye resolution. It is typical sectional drawing for demonstrating an example of the suitable manufacturing method of the light guide member of this invention. It is typical sectional drawing for demonstrating an example of the suitable manufacturing method of the light guide member of this invention. It is typical sectional drawing for demonstrating an example of the suitable manufacturing method of the light guide member of this invention. It is typical sectional drawing for demonstrating an example of the suitable manufacturing method of the light guide member of this invention. It is a perspective view which represents the light guide structure of an Example typically. It is a figure for demonstrating the structure of the light guide structure of an Example. It is a figure for demonstrating the structure of the light guide structure of an Example. It is a figure for demonstrating the structure of the light guide structure of an Example. It is a figure for demonstrating the structure of the light guide structure of an Example. It is a graph showing the relation between frequency and transmissivity. It is a graph showing the relation between frequency and absorptivity. It is a graph showing the relation between frequency and transmissivity. It is a graph showing the relation between frequency and transmissivity. It is a graph showing the relation between frequency and absorptivity. It is a schematic diagram for demonstrating the measuring method of light transmittance. It is sectional drawing which represents the light guide structure of an Example typically. It is a graph showing the relation between frequency and transmissivity. It is a graph showing the relation between frequency and absorptivity. It is sectional drawing which represents the light guide structure of an Example typically. It is sectional drawing which represents the light guide structure of an Example typically. It is a graph showing the relation between frequency and transmissivity. It is a graph showing the relation between frequency and absorptivity. It is sectional drawing which represents the light guide structure of an Example typically. It is a graph showing the relation between frequency and transmissivity. It is a graph showing the relation between frequency and absorptivity. It is sectional drawing which represents the light guide structure of an Example typically. It is a graph showing the relation between frequency and transmissivity. It is a graph showing the relation between frequency and absorptivity. It is a graph which shows the relationship between an average aperture diameter and the optimal average aperture ratio. It is a graph which shows the relationship between an average aperture ratio and the largest absorption factor. It is a graph which shows the relationship between an average aperture ratio and the largest absorption factor.

Hereinafter, the present invention will be described in detail.
Although the description of the configuration requirements described below is made based on the representative embodiments of the present invention, the present invention is not limited to such embodiments. In the drawings of this specification, the scale of each part is appropriately changed and shown for easy visual recognition.
In addition, in this specification, the numerical range represented using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.
Moreover, in the present specification, the terms "orthogonal" and "parallel" include the range of allowable errors in the technical field to which the present invention belongs. For example, “orthogonal” and “parallel” mean within ± 10 ° of strictly orthogonal or parallel, etc., and the error with respect to strictly orthogonal or parallel is 5 ° or less Is preferably, and more preferably 3 ° or less.
As used herein, "identical" and "identical" are intended to include error ranges generally accepted in the technical field. Further, in the present specification, the terms “all”, “all” or “entire” etc. include 100% as well as an error range generally accepted in the technical field, for example, 99% or more, The case of 95% or more, or 90% or more is included.

[Light guiding member and light guiding structure]
The light guide member of the present invention is
A sheet member having a plurality of through holes penetrating in the thickness direction,
The average opening diameter of the through holes is 1 μm or more and 250 μm or less,
The light reflectance in the visible light region of the sheet member is 50% or more,
Both sides of at least part of the seat member are in contact with the fluid,
It is a light guide member in which the peak value of the normal incidence sound absorption coefficient of the sheet member is 10% or more in the audible range.
The light guide structure of the present invention is a light guide structure in which the light guide member is disposed in a tubular duct member.
The configurations of the light guide member and the light guide structure of the present invention will be described using FIGS. 1 to 3.

FIG. 1 is a schematic perspective view showing an example of a preferred embodiment of the light guide structure of the present invention. FIG. 2 is a cross-sectional view in a direction parallel to the central axis of the light guide structure shown in FIG. FIG. 3 is a cross-sectional view in a direction perpendicular to the central axis of the light guide structure shown in FIG.
As shown in FIGS. 1 to 3, the light guide structure 100 a has a cylindrical shape in which the light guide member 10 formed by forming a plurality of through holes 14 penetrating in the thickness direction in the sheet member 12 is open at both end faces. The duct member 16 is disposed in parallel with the inner wall surface of the duct member 16.

As shown in FIG. 3, the duct member 16 is a cylindrical member. The light guide member 10 has the sheet member 12 formed in a cylindrical shape, and is disposed in the duct member 16 so that the center positions of the circles coincide with each other. Further, the outer diameter of the cylindrical sheet member 12 is smaller than the inner diameter of the duct member 16. Therefore, as shown in FIG. 3, a gap is formed between the light guide member 10 and the duct member 16. Therefore, both sides of the sheet member 12 are in contact with air (fluid).
In the present invention, a fluid is an object having a fluid property and transmitting sound as a compressional wave, and includes a gas such as air and a liquid such as water.

  Here, the inner surface of the sheet member 12 formed in a cylindrical shape has a light reflectance of 50% or more in the visible light region. Therefore, light incident from one end face of the cylindrically formed sheet member 12 is guided to the other end face while being reflected in the cylinder.

Further, in the sheet member 12, a plurality of fine through holes having an average opening diameter of 1 μm to 250 μm are formed. The light guide member 10 of the present invention absorbs sound by the friction between the inner wall surface of the through hole 14 and the air when the sound passes through the fine through hole 14 formed in the sheet member 12. Thereby, the peak value of the normal incidence sound absorption coefficient of the sheet member in the audible range becomes 10% or more.
The effect of sound absorption by the fine through holes will be described in detail later.

  For example, as shown in FIG. 4, such a light guide structure 100 a is installed in the building 200, one end is disposed on the outside of the building 200, and the other end is on the inside of the building 200. Be placed. In the example shown in FIG. 4, the building 200 is a building having three floors, and the light guiding structure 100a penetrates from the roof of the building 200 to the space of the first floor, and is bent 90 ° at the first floor portion, It is arranged to extend along the ceiling of the first floor, and the opening 102 formed at one end is disposed outside the roof and the opening 104 formed at the other end is the first floor. It is arranged in the space of. As shown in FIG. 4, an opening 102 is formed on the end face of the roof-side end of the light guide structure 100 a. A plurality of openings 104 are formed in the circumferential surface of the duct member 16 at the end on the first floor side of the light guide structure 100a.

Thereby, the light guiding structure 100a guides the light incident from the opening 102 formed at the end on the roof side to the first floor, and the light guiding structure 100a passes from the opening 104 formed at the end on the first floor to the first floor Illuminate the space of At that time, the sound outside the building 200 that is incident from the opening 102 on the roof side is absorbed by the fine through holes 14 of the light guide member 10. Similarly, the sound in the building 200 incident from the opening 104 on the first floor side is absorbed by the fine through holes 14 of the light guide member 10. Since the light guide member 10 absorbs sound due to the friction between the inner wall surface of the through hole 14 and air when sound passes through the fine through hole 14, high soundproofing performance can be obtained with a small volume. Therefore, since the inside of the duct member 16 is not blocked, it is possible to achieve both high soundproofing performance and high light guiding performance.
Hereinafter, the end on the light intake side and the opening 102 will be referred to as the end on the light receiving side and the opening 102, and the end on the light emitting side and the opening 104 may be referred to as the end and the opening 104 on the emission side. .

In the example shown in FIG. 4, the opening 102 on the light receiving side of the light guide structure 100 a is disposed outside the roof of the building 200, and the opening 104 on the emission side is disposed in the space of the first floor. However, the present invention is not limited thereto, and the opening 102 on the light receiving side may be disposed outside the building 200, and the opening 104 on the exit side may be disposed inside the building 200. For example, the opening 102 on the lighting side may be disposed outside from the wall surface (side surface) of the building 200. In addition, the opening 104 on the emission side may be disposed in the space of the second floor or the third floor.
Also, in the example shown in FIG. 4, the building 200 is a building having three floors, but is not limited to this, and is a building having one, two, or four or more floors. It may be.

Further, in the light guide structure shown in FIG. 1, the light guide member 10 is disposed in the entire area in the axial direction (longitudinal direction) in the duct member 16, but the invention is not limited thereto. It should just be arrange | positioned at at least one part of these.
From the viewpoint of light guiding performance and soundproofing performance, the light guiding member 10 is preferably disposed in the vicinity of the opening 104 on the exit side, and more preferably disposed in the entire axial direction of the duct member 16.

Further, in the light guide structure shown in FIG. 1, the light guide member 10 is formed in a cylindrical shape and disposed in the duct member 16, but the invention is not limited thereto, and is disposed in the duct member 16. If it can be, it can be set as various shapes, such as a flat shape and a curve shape.
From the viewpoint of light guiding performance and soundproofing performance, the light guiding member 10 preferably has a tubular shape.

  Further, in the light guide structure shown in FIG. 1, the inner surface of the sheet member 12 formed in a cylindrical shape has a high light reflectance (50% or more), but is not limited thereto. The outer surface of the sheet member 12 formed in a shape may have a high light reflectance, and it is most preferable that both surfaces have a high light reflectance.

Moreover, it is preferable that the light reflectance of the inner wall of the duct member 16 be high.
By increasing the light reflectance of the inner wall of the duct member 16, light can be suitably reflected and guided by the outer surface of the sheet member 12 formed in a cylindrical shape and the inner wall of the duct member 16. Further, by reflecting the light transmitted through the through holes 14 formed in the sheet member 12 by the inner wall of the duct member 16, the light guiding performance can be further enhanced.

Further, as shown in FIG. 4, the duct member 16 may have a bent portion. The bent portion may be curved with a radius of curvature as shown in FIG. 25 described later, or may be bent at a right angle (in an L shape) as shown in FIG.
When the duct member 16 has a bent portion, it is preferable to dispose the light guide member 10 so as to guide light in the bending direction of the bent portion.

Here, the light guide structure of the present invention may further include a partition member that divides the space between the light guide member and the duct member in the axial direction of the duct member.
FIG. 5 shows a cross-sectional view in the direction parallel to the central axis of another example of the light guide structure of the present invention.
A light guide structure 100 b shown in FIG. 5 has a tubular duct member 16, a light guide member 10 disposed in parallel to the inner wall of the duct member 16, and a partition member 18.

  The partition member 18 is arranged so as to divide the space between the light guide member 10 disposed with a gap and the duct member 16 in the axial direction of the duct member 16. In the example shown in FIG. 5, the partition member 18 is a plate-like member having an annular planar shape, and the outer diameter matches the inner diameter of the duct member 16 and the inner diameter matches the outer diameter of the light guide member 10 . The partition member 18 divides the space between the light guide member 10 and the duct member 16 in the axial direction of the duct member 16.

The space between the light guide member 10 and the duct member 16 functions as a resonator, which may cause a resonance phenomenon.
On the other hand, by dividing the space between the light guide member 10 and the duct member 16 by the partition member 18, each space becomes smaller, and the resonance frequency as the resonator shifts to the high frequency side, to the audible range Can reduce the effects of

In addition, assuming that each space partitioned by the partition member 18 is a cell, it is preferable to make the size (volume) of at least one of the plurality of cells different from the size of the other cells. Preferably the sizes are different.
As a result, the resonance frequency of each cell is different, so the influence on the audible range can be further reduced.

The material of the partition member 18 is not limited, and various metals and resins can be used. As a material of the partition member 18, it is preferable to use a material having a high light transmittance such as acryl or polycarbonate.
Specifically, the partition member 18 preferably has a visible light transmittance of 60% or more. Thereby, it can suppress that light is interrupted | blocked by the partition member 18, and light guide performance falls.
The visible light transmittance may be measured according to JIS K 7361-1: 1997 using a commercially available measuring device such as NDH4000 or SH-7000 manufactured by Nippon Denshoku Industries Co., Ltd.

  Moreover, it is preferable that the transmittance | permeability of the sound of the partition member 18 is low from a viewpoint of soundproof performance.

A porous sound absorber may be disposed between the light guide member 10 and the duct member 16. By arranging the porous sound absorber, higher soundproofing performance can be obtained in a wide frequency band.
When the porous sound absorber is disposed between the light guide member 10 and the duct member 16, the light guide performance may be degraded. Specifically, the light transmitted through the light guide member is strongly scattered by the porous sound absorber, so that the light transmittance is reduced without being guided well in the light guide direction. Since the porous sound absorber randomly has minute air portions, it inevitably becomes a light scatterer. Therefore, from the viewpoint of light guiding performance, it is preferable that the porous sound absorber is not disposed. In addition, the porous sound absorber is less durable than the sheet member. Also, replacement of porous sound absorbers, maintenance, etc. are not easy as compared with sheet members.
In addition, the porous sound absorber differs in that it also functions as a heat insulating material.

  In addition, the opening 102 on the light receiving side and / or the opening 104 on the output side of the light guide structure 100 a may be covered by a transparent member.

  Next, members constituting the light guide structure will be described.

[Duct member]
The duct member 16 is a cylindrical member having a hole penetrating inside for the purpose of ventilation, heat radiation, and movement of a substance. The duct member 16 may be installed as a light duct in a building, for example, an existing duct for ventilation, an intake pipe, an exhaust pipe, an indoor / outdoor pipe, an indoor duct used for a ventilation fan, a sleeve structure of an apartment etc. A light guide structure may be provided by arranging a light guide member on the duct member.
The cross-sectional shape of the duct member 16 is not limited, and may be various shapes such as a circular shape, an elliptical shape, a rectangular shape, a polygonal shape, and an irregular shape. Further, as described above, the duct member 16 is not limited to the straight tubular shape, and may have a bent portion.

The material of the duct member 16 is not limited, and various metal materials, resin materials, fiber reinforced plastics such as carbon fibers, concrete, mortar, wood and the like can be appropriately used.
From the viewpoint of light guiding performance, the duct member is preferably made of a metal material having a high light reflectance.

[Light guiding member]
The light guide member 10 includes a sheet member 12 having a plurality of through holes 14 penetrating in the thickness direction.
The light guide member 10 may be formed of the sheet member 12 alone, but as shown in FIGS. 6 and 7, the sheet member 12 may be stacked on the frame 16.

[Sheet member]
The top view of the light guide member 10 (sheet member 12) is shown in FIG.
The average opening diameter of the plurality of through holes in the sheet member 12 is 1 μm or more and less than 250 μm. By this, sound is absorbed by the friction between the inner wall surface of the through hole and air when sound passes through the fine through hole. That is, even if there is a closed space, the volume of the closed space is different from the volume optimum for the conventional Helmholtz resonance, and sound is absorbed by a mechanism that is not a resonance with the closed space. As described above, the light guiding member 10 does not use the principle of Helmholtz resonance in which the connection between the air layer in the through hole and the air layer in the closed space functions as a mass spring to cause resonance to absorb sound.
Here, in the present invention, the peak value of the normal incidence sound absorption coefficient of the sheet member in the audible range is 10% or more.
In addition, the evaluation method of the normal incidence sound absorption coefficient of a sheet | seat member is performed according to ISO10534-2: 1998. If there is an outer shell structure and the sheet member and the outer shell structure are arranged at a distance, the normal incidence sound absorption coefficient of the sheet member is evaluated with the back distance. For example, when the wall surface of the duct member is disposed 1 cm apart on the back surface of the sheet member, the vertical incident sound absorption coefficient of the system in which the rigid wall is disposed 1 cm apart on the back surface of the sheet member is evaluated The incident sound absorption coefficient.
From the viewpoint of soundproofing performance, the peak value of the normal incidence sound absorption coefficient of the sheet member in the audible range is preferably 30% or more, and more preferably 50% or more.

The inventors of the present invention have found that the sound absorption mechanism of the sheet member having a plurality of fine through holes is the heat energy of the sound due to the friction between the inner wall surface of the through hole and the air when the sound passes through the fine through holes. It was estimated to be a change to energy. This mechanism is different from the mechanism due to resonance because it is caused by the fine through-hole size. The path directly passing through as a sound in the air by the through hole has a much smaller impedance than the path once converted to membrane vibration and then emitted again as a sound. Therefore, the sound can easily pass through the path of the through hole which is finer than the membrane vibration. When passing through the through hole portion, the sound is concentrated and passed from the wide area on the entire sheet member to the narrow area of the through hole. The local velocity is extremely increased by the collection of sounds in the through holes. Because friction correlates with speed, friction increases in the fine through holes and is converted to heat.
When the average opening diameter of the through hole is small, the ratio of the edge length of the through hole to the opening area is increased, and therefore, it is considered that the friction generated at the edge or the inner wall surface of the through hole can be increased. By increasing the friction when passing through the through holes, sound energy can be converted into heat energy and absorbed.

  Further, according to the study of the present inventors, an optimum ratio exists to the average aperture ratio of the through holes, and in particular, when the average aperture diameter is relatively large such as about 50 μm or more, the smaller the average aperture ratio, the higher the absorption rate. I found out. When the average aperture ratio is large, the sound passes through each of the many through holes, whereas when the average aperture ratio is small, the number of the through holes decreases, and therefore the sound passes through one through hole. It is believed that the noise increases and the local velocity of air as it passes through the through-hole is further increased, and the friction generated at the edge and the inner wall surface of the through-hole can be further increased.

As described above, the sheet member does not require a closed space on the back surface and functions as a single sheet member having a through hole, so the size and mass can be reduced.
Further, as described above, since the sheet member absorbs sound by friction when sound passes through the through hole, it can absorb sound regardless of the frequency band of sound, and can absorb sound in a wide band.
Moreover, since it has a through hole, light can be transmitted while being scattered.
In addition, since it functions by forming fine through holes, there is a high degree of freedom in material selection, and problems of contamination of the surrounding environment and environmental resistance performance can be reduced because materials can be selected according to the environment. be able to.

In addition, since the sheet member has a fine through hole, even if a liquid such as water adheres to the sheet member, water does not block the through hole by the surface tension because water avoids the portion of the through hole. Performance is unlikely to decline.
Moreover, since it is a thin plate-like (film-like) member, it can be curved according to the place to arrange.
In addition, if the material of the sheet member is a metal material, it also functions as a reflector against radiant heat. That is, it is possible to reflect also the heat which intrudes into the duct member from the outside such as the wall.
In addition, since the average opening diameter of the through holes is small, it is difficult to visually recognize the through holes. That is, for example, when the sheet member is formed by forming a fine through hole in an aluminum foil, it looks like an aluminum foil without a through hole, and therefore, it is excellent in appearance.
Because the through holes are small, it is difficult for insects to enter the inside and dust is difficult to enter and exit.
Further, the light guiding performance and the sound absorbing performance can be provided while maintaining the intake and exhaust performance of the duct member.

In addition, at least one surface of the light guide member 12 has a light reflectance of 50% or more in the visible light region. Thereby, the light guide member 12 can reflect and guide light.
From the viewpoint of light guiding performance, the light reflectance in the visible light region of the light guide member 12 is preferably 70% or more, and more preferably 85% or more.
In the present specification, the visible light region is a wavelength range of 380 nm to 780 nm. The light reflectance is a ratio of light (reflected light) reflected in the normal direction to light (incident light) incident from the normal direction of the light guide member 12. A spectrophotometer can be used for measurement. Specifically, for example, by using a spectrophotometer system such as Hitachi Ltd .: U4000, U4100, UH4150, it is possible to measure the transmittance, reflectance, and absorptivity of visible light. This can be used to average the spectrum of reflectance in the visible light region to obtain light reflectance in the visible region.

  From the viewpoint of soundproofing performance and light guiding performance, the average opening diameter of the plurality of through holes 14 of the sheet member 12 is 1 μm to 250 μm, preferably 1 μm to less than 100 μm, and more preferably 5 μm to 50 μm. This is because the smaller the average opening diameter of the through hole, the larger the ratio of the length of the edge of the through hole contributing to the friction in the through hole to the opening area of the through hole, and the friction is more likely to occur. In addition, if the average opening diameter is too small, the viscous resistance at the time of passing through the through hole is too high and the sound does not pass sufficiently, so that the sound absorbing effect can not be sufficiently obtained even if the aperture ratio is increased.

Further, from the viewpoint of soundproofing performance and light guiding performance, the average aperture ratio of the through holes 14 of the sheet member 12 is preferably 0.1% to 20%, and more preferably 1% to 10%. .
In particular, from the viewpoint of light guiding performance, when the average aperture ratio is too large, the area of the light-reflecting area of the sheet member decreases, so the average aperture ratio is preferably 20% or less.

  The thickness of the sheet member 12 is preferably 5 μm or more and 300 μm or less, and more preferably 10 μm or more and 100 μm or less, from the viewpoint of soundproof performance, downsizing, weight, productivity, and the like. It is considered that the sound absorbing performance is further improved because the friction energy received when the sound passes through the through hole is larger as the thickness is thicker. Moreover, when it is extremely thin, it is difficult to handle it and it is easy to break it. On the other hand, it is preferable that the size, weight and air permeability be small. In the case of using etching or the like as the method of forming the through holes, the thicker the film, the longer it takes to produce the film, and therefore the thinner is desirable from the viewpoint of productivity. In addition, since it becomes more difficult to form fine through holes of 250 μm or less as the thickness becomes thicker, the thickness is preferably thinner also from this point.

Here, the plurality of through holes 14 formed in the sheet member 12 have an average opening diameter of 1 μm to less than 100 μm, the average opening diameter of the plurality of through holes 14 is phi (μm), and the thickness of the sheet member 12 is t (t When the average aperture ratio rho of the through holes 14 is in the range of more than 0 and less than 1 and rho_center = (2 + 0.25 × t) × phi ^−1.6 , rho_center− (0.052 × It is preferable to have a configuration in which the upper limit is rho_center + (0.795 × (phi / 30) ⁻² ) with (phi / 30) ⁻² ) as the lower limit.

Assuming that the average opening diameter of the through holes is 1 μm or more and less than 100 μm, the average opening diameter of the plurality of through holes 14 is phi (μm), and the thickness of the sheet member 12 is t (μm) rho is a range of greater than 0 and less than 1 and rho_center = (2 + 0.25 × t) × phi ^−1.6 with rho_center− (0.052 × (phi / 30) ⁻² ) as the lower limit, rho_center + ( Higher sound absorption effects can be obtained by setting the upper limit of 0.795 × (phi / 30) ⁻² ).

Further, the average aperture ratio rho is preferably in the range of rho_center−0.050 × (phi / 30) ⁻² or more, rho_center + 0.505 × (phi / 30) ⁻² or less, and rho_center−0.048 × (phi / 30) ⁻² or more The range of rho_center + 0.345 × (phi / 30) ^-2 or less is more preferable, and the range of rho_center-0.085 × (phi / 20) ^-2 or more, rho_center + 0.35 × (phi / 20) ^-2 or less is more preferable, The range of (rho_center−0.24 × (phi / 10) ⁻² ) or more and (rho_center + 0.57 × (phi / 10) ⁻² ) or less is particularly preferable, and (rho_center−0.185 × (phi / 10) ⁻² ) or more, The range of (rho_center + 0.34 × (phi / 10) ⁻² ) or less is most preferable. This point will be described in detail in a simulation to be described later.

The average opening diameter of the through holes is the periphery of the obtained SEM photograph obtained by photographing the surface of the sheet member at a magnification of × 200 using a high resolution scanning electron microscope (SEM) from one surface of the sheet member. The 20 through holes having a ring shape are extracted, the diameter of the opening is read, and the average value of these is calculated as the average diameter of the opening. If the number of the through holes is less than 20 in one SEM photograph, the SEM photographs are taken at another position in the periphery and counted until the total number reaches 20.
In addition, the opening diameter measured the area of a through-hole part, respectively, and evaluated using the diameter (circle equivalent diameter) when replacing with the circle | round | yen which becomes the same area. That is, since the shape of the opening of the through hole is not limited to a substantially circular shape, when the shape of the opening is non-circular, evaluation was made based on the diameter of the circle having the same area. Therefore, for example, even in the case of a through hole having a shape in which two or more through holes are integrated, this is regarded as one through hole, and the circle equivalent diameter of the through hole is defined as the opening diameter.
In these operations, for example, the circle equivalent diameter, the aperture ratio and the like can all be calculated by Analyze Particles using “Image J” (https://imagej.nih.gov/ij/).

  For the average aperture ratio, the surface of the sheet member is photographed at a magnification of 200 times from directly above using a high resolution scanning electron microscope (SEM), and the 30 mm × 30 mm field of view (5 places) of the obtained SEM photograph , And binarized with image analysis software etc. to observe the through hole part and the non-through hole part, and the ratio (opening area / geometrical) from the total of the open area of the through holes and the area of the visual field (geometrical area) The average value in each visual field (five places) is calculated as an average aperture ratio.

Here, in the sheet member, the plurality of through holes may be regularly arranged or randomly arranged. It is preferable to arrange at random from the viewpoints of productivity of fine through holes, robustness of sound absorption characteristics, and suppression of sound diffraction. With regard to the diffraction of sound, when the through holes are periodically arranged, the phenomenon of sound diffraction occurs according to the period of the through holes, and there is a concern that the sound bends due to diffraction and the traveling direction of the noise is divided into plural. Random is a state in which there is no periodicity such as complete alignment, and while the absorption effect by each through hole appears, the diffraction phenomenon by the minimum distance between through holes does not occur.
In addition, since it is easier to form a random pattern at one time, such as surface treatment, for mass production rather than the process of producing a periodic array, it is preferable that the array be randomly arranged from the viewpoint of productivity .

In the present invention, the arrangement of the through holes at random is defined as follows.
When the structure is completely periodic, strong diffracted light appears. In addition, even if the position of the periodic structure is only a part of which is different, diffracted light appears due to the remaining structure. Since the diffracted light is a wave formed by superposition of the scattered light from the basic cell of the periodic structure, even if only a part of it is disturbed, the interference by the remaining structure is a mechanism that generates the diffracted light.
Therefore, as the number of basic cells disordered from the periodic structure increases, the intensity of the diffracted light decreases because the scattered light that interferes with the diffracted light decreases.
Therefore, "random" in the present invention indicates that at least 10% of the through holes in the whole are in a state of being shifted from the periodic structure. From the above discussion, it is preferable that the number of basic cells deviated from the periodic structure is more desirable to suppress diffracted light, so a structure in which 50% of the whole deviates is preferable, and a structure in which 80% of the whole deviates is more preferable Further, a structure in which 90% of the whole is deviated is more preferable.

As verification of deviation, it is possible to take an image in which five or more through holes fit and analyze it. A more accurate analysis can be performed if the number of through holes to be stored is large. The image can be used by an optical microscope, an SEM, or any other image capable of recognizing the positions of a plurality of through holes.
In the photographed image, attention is paid to one through hole, and the distance to the surrounding through hole is measured. The closest distance is a1, the second, third, and fourth closest distances are a2, a3, and a4, respectively. At this time, when two or more distances in a1 to a4 coincide with each other (for example, let the coincident distance be b1), the through hole can be judged as a hole having a periodic structure with respect to the distance of b1. On the other hand, when none of the distances a1 to a4 match, the through hole can be determined as a through hole shifted from the periodic structure. This operation is performed on all through holes on the image to make a determination.
Here, it is assumed that the above “matching” matches up to the deviation of Φ when the focused hole diameter of the through hole is Φ. That is, it is assumed that a2 and a1 coincide with each other when there is a relationship of a2-Φ <a1 <a2 + a. This is because it is considered that scattering occurs in the range of the hole diameter Φ because the diffracted light considers the scattered light from each through hole.
Next, for example, the number of “through holes having a periodic structure with respect to the distance of b1” is counted, and a ratio to the number of all through holes on the image is obtained. Assuming that this ratio is c1, the ratio c1 is the ratio of through holes having a periodic structure, 1-c1 is the ratio of through holes deviated from the periodic structure, and 1-c1 is the numerical value that determines the above "random" and Become. If there are a plurality of distances, for example, "a through hole having a periodic structure for a distance of b1" and "a through hole having a periodic structure for a distance of b2", b1 and b2 are separately counted. Assuming that the ratio of the periodic structure is c1 for the distance of b1 and the ratio of the periodic structure is c2 for the distance of b2, if (1-c1) and (1-c2) are both 10% or more, the structure It will be random.
On the other hand, when either (1-c1) or (1-c2) is less than 10%, the structure has a periodic structure and is not “random”. Thus, the structure is defined as "random" when the condition "random" is satisfied for any of the ratios c1, c2, ....

Further, the plurality of through holes may be through holes of one kind of opening diameter, or may be through holes of two or more kinds of opening diameter. From the viewpoint of productivity, the viewpoint of durability, etc., it is preferable to be composed of through holes having two or more kinds of opening diameters.
As for the productivity, as in the case of the above-described random arrangement, if the variation in the aperture diameter is allowed from the viewpoint of performing a large amount of etching, the productivity is improved. Also, from the viewpoint of durability, the size of dust and dirt varies depending on the environment, so if it is a through hole of one kind of opening diameter, it affects all the holes when the size of the main dirt almost matches the through hole Will give. By providing through holes of a plurality of opening diameters, the device can be applied to various environments.

Further, according to the manufacturing method described in International Publication WO 2016/060037 or the like, it is possible to form the through hole having the largest diameter inside, in which the hole diameter is expanded inside the through hole. With this shape, dust (a dust, toner, non-woven fabric, loose foam, etc.) of about the size of a through hole is less likely to be clogged inside, and the durability of the film having the through hole is improved.
Dust larger than the diameter of the outermost surface of the through hole does not intrude into the through hole, while dust smaller than the diameter can pass through the through hole as it is because the internal diameter is large.
This is the reverse shape and considering the shape of the interior that is recessed, the dust that has passed through the outermost surface of the through hole is caught on the portion with a smaller diameter inside, compared to the fact that the dust tends to remain as it is It can be seen that the shape with the largest diameter functions advantageously in the suppression of dust clogging.
Also, as in the so-called tapered shape, in the shape in which one surface of the film has the largest diameter and the inner diameter decreases substantially monotonically, the largest diameter from the largest diameter "size of dust> size of the other surface" When the dust that satisfies the relationship of “diameter” enters, the internal shape functions like a slope and the possibility of clogging in the middle becomes even greater.

Further, from the viewpoint of increasing the friction when sound passes through the through hole, the inner wall surface of the through hole is preferably roughened. Specifically, the surface roughness Ra of the inner wall surface of the through hole is preferably 0.1 μm or more, more preferably 0.1 μm to 10.0 μm, and 0.2 μm to 1.0 μm. It is more preferable that there be.
Here, the surface roughness Ra can be measured by measuring the inside of the through hole with an AFM (Atomic Force Microscope). As the AFM, for example, SPA300 manufactured by Hitachi High-Tech Science Co., Ltd. can be used. The cantilever can be measured in DFM (Dynamic Force Mode) mode using OMCL-AC200TS. Since the surface roughness of the inner wall surface of the through hole is about several microns, it is preferable to use AFM in terms of having a measurement range and accuracy of several microns.

Moreover, the average particle diameter of a convex part can be calculated by regarding each one of the convex part of the unevenness | corrugation in a through-hole as particle | grains from the SEM image in a through-hole.
Specifically, an SEM image (field of view of about 1 mm × 1 mm) taken at a magnification of 2000 × is taken into Image J, and binarized into black and white so that the convex part becomes white, and the area of each convex part is analyzed Calculated by Particles. The circle equivalent diameter which assumed the circle | round | yen which becomes the same area as each area is calculated | required about each convex part, and the average value is calculated as an average particle diameter.
The average particle diameter of the convex portion is preferably 0.1 μm or more and 10.0 μm or less, and more preferably 0.15 μm or more and 5.0 μm or less.

Here, in the simulation result to be described later, the velocity in the through hole was measured after calculation in the simulation of the design corresponding to the first embodiment. The velocity in the through hole is about 5 × 10 ^-2 (m / s) when the sound pressure is 1 [Pa] (= 94 dB) and about 1 × 10 ^-3 (m / s) when 60 dB.
When sound with a frequency of 2500 Hz is absorbed, the local velocity indicates the local moving velocity of the medium that mediates the sound wave. From this, it was assumed that the particles were vibrating in the penetration direction of the through hole, and the movement distance was determined. Because the sound is vibrating, its amplitude is a distance that can be moved within a half cycle. At 2500 Hz, since one cycle is 1/2500 seconds, half of the time can be in the same direction. The maximum travel distance (acoustic travel distance) in the sound wave half cycle determined from the local velocity is 10 μm at 94 dB and 0.2 μm at 60 dB. Therefore, since the friction is increased by having the surface roughness about this acoustic movement distance, the range of the surface roughness Ra described above and the range of the average particle diameter of the convex portion are preferable.

Here, from the viewpoint of the visibility of the through holes, the average opening diameter of the plurality of through holes formed in the sheet member is preferably 50 μm or less, and more preferably 20 μm or less.
When a sheet member having fine through holes, which is used in the light guide structure of the present invention, is disposed in a visible place, if the through holes themselves are visible, the designability is impaired and the holes are open in appearance It is desirable that the through hole is difficult to see because it is anxious.

First, the visibility of one through hole is examined.
The resolution of the human eye is discussed below in the case of eyesight 1 below.
The definition of visual acuity 1 is to look with resolution of one minute. This shows that 87 μm can be resolved at a distance of 30 cm. The relationship between the distance and the resolution in the case of the visual acuity 1 is shown in FIG.
Whether or not the through hole can be seen is strongly related to the above vision. Just as the visual acuity test is performed with the recognition of the gap portion of the Landolt's ring, it is dependent on the resolution whether a space between two points and / or two lines is visible. That is, in the case of a through hole having an opening diameter smaller than the resolution of the eye, visual recognition is difficult because the distance between the edges of the through hole can not be disassembled by eyes. On the other hand, the shape of the through hole having an aperture diameter equal to or greater than the resolution of the eye can be recognized.
In the case of eyesight 1, a 100 μm through hole can be disassembled from a distance of 35 cm, but a 50 μm through hole can not be disassembled until it reaches 18 cm and a 20 μm through hole can reach 7 cm distance. Therefore, even if the 100 μm through hole can be visually recognized and anxious, using the 20 μm through hole, it can not be recognized unless approaching an extremely close distance of 1⁄5. Therefore, a smaller opening diameter is advantageous for hiding the through hole. When the light guide structure is used in a wall or in a car, the distance from the observer is generally several tens cm, but in this case, the opening diameter is about 100 μm.

  Next, light scattering caused by the through holes will be discussed. Since the wavelength of visible light is about 400 nm to 800 nm (0.4 μm to 0.8 μm), the aperture diameter of several 10 μm discussed in the present invention is sufficiently larger than the optical wavelength. In this case, the scattering cross section (an amount indicating how strongly an object is scattered, a unit is an area) in visible light substantially corresponds to the geometrical cross section, ie, in this case, the cross section of the through hole. That is, it can be seen that the size of the visible light scattered is proportional to the square of the radius of the through hole (half of the circle equivalent diameter). Therefore, the larger the through hole is, the larger the light scattering intensity becomes with the square of the through hole radius. Since the visibility of the through holes alone is proportional to the amount of light scattering, it is easier to see when the through holes are large even if the average aperture ratio is the same.

Finally, the difference between the periodic arrangement and the random arrangement having no periodicity in the arrangement of the through holes is examined. In a periodic arrangement, light diffraction phenomena occur according to the period. In this case, when a white light to be transmitted, a white light to be reflected, a broad spectrum of light, and the like are hit, the light is diffracted and appears to be discolored like a rainbow, or strongly reflected at a specific angle, etc. The pattern is noticeable by being seen in various ways.
On the other hand, when arranged at random, the above-mentioned diffraction phenomenon does not occur.

The material of the sheet member is not limited, and aluminum, titanium, nickel, permalloy, 42 alloy, kovar, nichrome, copper, beryllium, phosphor bronze, brass, nickel, tin, zinc, iron, tantalum, niobium, molybdenum, zirconium , Various metals such as gold, silver, platinum, palladium, steel, tungsten, lead and iridium; PET (polyethylene terephthalate), TAC (triacetyl cellulose), polyvinylidene chloride, polyethylene, polyvinyl chloride, polymethylbenzene, Resin materials such as COP (cycloolefin polymer), polycarbonate, zeonor, PEN (polyethylene naphthalate), polypropylene, and polyimide can be used. Furthermore, glass materials such as thin film glass; CFRP (carbon fiber reinforced plastics) and fiber reinforced plastic materials such as GFRP (glass fiber reinforced plastics) can also be used.
In addition, the light reflectance of the original material is imparted with the function of light reflection, such as deposition of metal such as silver and aluminum, deposition of dielectric multilayer mirror such as SiO ₂ -TiO ₂ laminated film, etc. on the surface of these materials. A small member can also be used.
A metal material is used from the viewpoints of being high in Young's modulus and difficult to vibrate even if the thickness is thin, and easy to obtain the sound absorption effect by the friction in the minute through holes, and to increase the light reflectance. Is preferred. Among them, it is preferable to use aluminum from the viewpoints of lightness, easy formation of minute through holes by etching, etc., availability, cost and the like.

Moreover, when using a metal material, you may metal-plate on the surface from a viewpoint of suppression of rust etc.
Furthermore, the average opening diameter of the through holes may be adjusted to a smaller range by metal plating at least on the inner surface of the through holes.

In addition, by using a conductive material such as a metal material which is not electrically charged as the material of the sheet member, fine dust and dirt are not attracted to the film by static electricity, and dust and dirt are not generated in the through holes of the sheet member. It is possible to suppress the reduction in sound absorption performance due to clogging with dust and the like.
Moreover, heat resistance can be made high by using a metal material as a material of a sheet | seat member. In addition, ozone resistance can be enhanced.
Moreover, when using a metal material as a sheet member, an electromagnetic wave can be shielded.

In addition, since the metal material has a large reflectance to radiation heat by far-infrared rays, using a metal material as the material of the sheet member also functions as a heat insulating material that prevents heat transfer due to the radiation heat. At this time, although a plurality of through holes are formed in the sheet member, the sheet member functions as a reflective film because the opening diameter of the through holes is small.
A structure in which a plurality of fine through holes are opened in metal is known to function as a high pass filter of frequency. For example, a window with a metal mesh of a microwave oven has a property of shielding visible light that is high frequency while passing microwaves used in the microwave oven. In this case, when the hole diameter of the through hole is 、 and the wavelength of the electromagnetic wave is λ, the long wavelength component in the relationship of << λ does not pass, and the short wavelength component with Φ> λ functions as a transmissive filter.
Now consider the response to radiant heat. Radiant heat is a heat transfer mechanism in which far infrared rays are emitted from an object in accordance with the object temperature and transmitted to another object. From the Wien's radiation law, radiant heat is distributed around λ = 10 μm in a room temperature environment, and heat is effectively radiated up to a wavelength about 3 times (up to 30 μm) on the long wavelength side It is known to contribute to Considering the relationship between the hole diameter Φ of the high-pass filter and the wavelength λ, the component of λ> 20 μm is strongly shielded in the case of == 20 μm, while the relationship of >> λ is obtained in the case of == 50 μm It will propagate through. That is, since the hole diameter Φ is several tens of μm, the radiation heat propagation performance largely changes depending on the difference in the hole diameter 分 か る, and it is understood that the smaller the hole diameter す な わ ち, that is, the smaller the average opening diameter, the radiation heat cut filter functions. Therefore, from the viewpoint of a heat insulating material that prevents heat transfer due to radiant heat, the average opening diameter of the through holes formed in the sheet member is preferably 20 μm or less.

  In addition, the sheet member is appropriately subjected to surface treatment (plating treatment, oxide film treatment, surface coating (fluorine, ceramic), etc.) according to the material to improve the durability or light reflectivity of the sheet member. be able to. For example, in the case of using aluminum as the material of the sheet member, an oxide film can be formed on the surface by performing an alumite treatment (anodic oxidation treatment) or a boehmite treatment. By forming an oxide film on the surface, corrosion resistance, abrasion resistance, scratch resistance and the like can be improved. Further, by adjusting the treatment time and adjusting the thickness of the oxide film, it is possible to adjust the color tone by optical interference.

In addition, coloring can be performed on the sheet member. As a method of applying these, a method may be appropriately selected according to the material of the sheet member and the state of the surface treatment. For example, printing using an inkjet method can be used. Moreover, when using aluminum as a material of a sheet member, highly durable coloring can be performed by performing a color alumite process. The color alumite treatment is a treatment in which the surface is subjected to alumite treatment, then impregnated with a dye, and then the surface is sealed. By performing anodizing after forming the through holes, the anodic oxide film is formed only on the aluminum portion, so that the dye covers the through holes to perform the decoration without reducing the sound absorption characteristics. it can.
By coloring the sheet member, the light reflectance varies depending on the wavelength in the visible light region, so that light of a specific color (wavelength) can be guided.

  In addition, the surface of the sheet member may be roughened. By roughening the surface of the sheet member, light can be guided while being diffused. On the other hand, if the surface roughness is too rough, the light reflectance will be low. Accordingly, the surface roughness Ra of the surface of the sheet member is preferably 0.005 μm to 1 μm, and more preferably 0.01 μm to 0.5 μm.

<Aluminum base material>
The aluminum base used as the sheet member is not particularly limited, and, for example, a known aluminum base such as alloy No. 1085, 1N30, or 3003 described in JIS Standard H4000 can be used. In addition, an aluminum base material is an alloy plate which has aluminum as a main component and contains a trace amount of different elements.
The thickness of the aluminum substrate is not particularly limited, but is preferably 5 μm to 1000 μm, more preferably 7 μm to 200 μm, and particularly preferably 10 μm to 100 μm.

[Method of manufacturing sheet member]
Next, a method of manufacturing a sheet member used for the light guide structure of the present invention will be described by using an aluminum base as an example.
The manufacturing method of the sheet member using an aluminum base material is
A film forming step of forming a film having aluminum hydroxide as a main component on the surface of an aluminum substrate;
A through hole forming step of forming a through hole by performing a through hole forming process after the film forming step;
A film removing step of removing the aluminum hydroxide film after the through hole forming step;
Have.
By having the film forming step, the through hole forming step, and the film removing step, it is possible to preferably form a through hole having an average opening diameter of 1 μm to 250 μm.

  Next, each process of the manufacturing method of a light guide structure is demonstrated using FIGS. 10-13, Then, each process is explained in full detail.

10 to 13 are schematic cross-sectional views showing an example of a preferred embodiment of a method for manufacturing a sheet member using an aluminum base.
As shown in FIGS. 10 to 13, the method for manufacturing the sheet member performs a film forming process on one main surface of the aluminum base 11 to form an aluminum hydroxide film 13 (FIG. 10 and FIG. 11) and an electrolytic dissolution process after the film forming step to form the through holes 14 and forming the through holes in the aluminum base 11 and the aluminum hydroxide film 13 (FIGS. 11 and 12) And a film removing step (FIGS. 12 and 13) of removing the aluminum hydroxide film 13 after the through hole forming step, and producing a light guide structure including the sheet member 12 having the through hole 14 It is.
In the sheet member manufacturing method, after the film removing step, the sheet member 12 having the through holes 14 is subjected to electrochemical graining treatment to roughen the surface of the sheet member 12. It is preferable to have.

  Since small holes are easily formed in the aluminum hydroxide film, after the film formation step of forming the aluminum hydroxide film, electrolytic dissolution treatment is performed in the through hole formation step to form the through holes, whereby the average opening diameter is 1 μm. Through-holes of not less than 250 μm, particularly not less than 1 μm and less than 100 μm can be formed.

[Coating process]
In the present invention, the film forming step of the method for producing a sheet member is a step of forming a film of aluminum hydroxide by subjecting the surface of the aluminum substrate to a film forming treatment.

<Coating process>
The film formation process is not particularly limited, and, for example, the same process as the conventionally known aluminum hydroxide film formation process can be performed.
As a film formation process, the conditions and apparatus which were described in the <0013>-<0026> stage of Unexamined-Japanese-Patent No. 2011-201123 are employable suitably, for example.

In the present invention, the conditions for the film formation treatment can not be determined indiscriminately because they vary depending on the electrolyte used, but generally, the electrolyte concentration is 1 to 80 mass%, and the solution temperature is 5 to 70 ° C. It is appropriate that the current density is 0.5 to 60 A / dm ² , the voltage is 1 to 100 V, and the electrolysis time is 1 second to 20 minutes, and it is adjusted to obtain a desired amount of film.

In the present invention, it is preferable to carry out the electrochemical treatment using nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid or a mixed acid of two or more of these acids as the electrolytic solution.
When the electrochemical treatment is performed in an electrolytic solution containing nitric acid and hydrochloric acid, direct current may be applied between the aluminum base and the counter electrode, and alternating current may be applied. When a direct current is applied to the aluminum substrate, the current density is preferably 1 to 60 A / dm ^2, and more preferably 5~50A / dm ^2. When performing electrochemical processing continuously, it is preferable to carry out to the aluminum base material by the liquid electric power feeding system which supplies electric power through electrolyte solution.

In the present invention, the amount of aluminum hydroxide film formed by film formation treatment is preferably a 0.05 to 50 g / m ^2, and more preferably 0.1 to 10 g / m ^2.

[Through hole forming process]
The through hole forming step is a step of performing electrolytic dissolution treatment after the film forming step to form a through hole.

<Electrolytic dissolution treatment>
The electrolytic dissolution treatment is not particularly limited, and an acidic solution can be used as the electrolytic solution using direct current or alternating current. Among them, electrochemical treatment is preferably performed using at least one or more acids of nitric acid and hydrochloric acid, and electrochemical treatment is performed using a mixed acid of at least one or more of sulfuric acid, phosphoric acid and oxalic acid in addition to these acids. Is more preferred.

  In the present invention, as an acidic solution which is an electrolytic solution, in addition to the above-mentioned acids, U.S. Patents 4,671,859, 4,661,219, 4,618,405, 4,600,482, 4,566,960, 4,566,958, 4,566,959, 4,416,972, 4,374,710 It is also possible to use the electrolytes described in the specifications of U.S. Pat. Nos. 4,336,113 and 4,184,932.

  The concentration of the acidic solution is preferably 0.1 to 2.5% by mass, and particularly preferably 0.2 to 2.0% by mass. Moreover, it is preferable that it is 20-80 degreeC, and, as for the liquid temperature of an acidic solution, it is more preferable that it is 30-60 degreeC.

The aqueous solution mainly composed of the acid is a nitrate compound having nitrate ion such as aluminum nitrate, sodium nitrate or ammonium nitrate in an aqueous solution of acid having a concentration of 1 to 100 g / L or hydrochloric acid such as aluminum chloride, sodium chloride or ammonium chloride At least one of a hydrochloric acid compound having an ion and a sulfate compound having a sulfate ion such as aluminum sulfate, sodium sulfate and ammonium sulfate can be added and used in a range from 1 g / L to saturation.
Moreover, the metal contained in aluminum alloys, such as iron, copper, manganese, nickel, titanium, magnesium, a silica, may be melt | dissolving in the aqueous solution which has the said acid as a main. Preferably, it is preferable to use a solution in which aluminum chloride, aluminum nitrate, aluminum sulfate or the like is added to an aqueous solution with an acid concentration of 0.1 to 2% by mass so that the aluminum ion is 1 to 100 g / L.

  Although direct current is mainly used for the electrochemical dissolution process, the alternating current power source wave is not particularly limited when using alternating current, and sine wave, rectangular wave, trapezoidal wave, triangular wave or the like is used, Among them, rectangular waves or trapezoidal waves are preferable, and trapezoidal waves are particularly preferable.

(Nitric acid electrolysis)
In the present invention, through holes having an average opening diameter of 1 μm to 250 μm are easily formed by electrochemical dissolution treatment using an electrolyte mainly composed of nitric acid (hereinafter also referred to as “nitric acid dissolution treatment”). can do.
Here, in the nitric acid dissolution treatment, the condition that the average current density is 5 A / dm ² or more and the amount of electricity is 50 C / dm ² or more using a direct current because it is easy to control the dissolution point of through hole formation It is preferable that it is the electrolytic treatment given by. The average current density is preferably 100 A / dm ² or less, and the amount of electricity is preferably 10000 C / dm ² or less.
Further, the concentration and temperature of the electrolyte in nitric acid electrolysis are not particularly limited, and electrolysis is carried out at 30 to 60 ° C. using a high concentration nitric acid electrolyte having a concentration of 15 to 35 mass%, for example. Electrolysis can be performed at a high temperature, for example, 80 ° C. or more, using a 7 to 2% by mass nitric acid electrolyte.
In addition, electrolysis can be performed using an electrolytic solution obtained by mixing at least one of sulfuric acid, oxalic acid and phosphoric acid at a concentration of 0.1 to 50% by mass with the above nitric acid electrolytic solution.

(Hydrochloric acid electrolysis)
In the present invention, through-holes having an average opening diameter of 1 μm to 250 μm can be easily obtained by electrochemical dissolution treatment using an electrolyte mainly composed of hydrochloric acid (hereinafter also abbreviated as “hydrochloric acid dissolution treatment”). It can be formed.
Here, in the hydrochloric acid dissolution treatment, the condition that the average current density is 5 A / dm ² or more and the amount of electricity is 50 C / dm ² or more using a direct current because it is easy to control the dissolution point of through hole formation It is preferable that it is the electrolytic treatment given by. The average current density is preferably 100 A / dm ² or less, and the amount of electricity is preferably 10000 C / dm ² or less.
Further, the concentration and temperature of the electrolyte solution in hydrochloric acid electrolysis are not particularly limited, and electrolysis is carried out at 30 to 60 ° C. using a high concentration, for example, a hydrochloric acid electrolyte solution having a hydrochloric acid concentration of 10 to 35 mass%. Electrolysis can be performed at a high temperature, for example, 80 ° C. or more, using a 7 to 2% by mass hydrochloric acid electrolyte solution.
In addition, electrolysis can be performed using an electrolytic solution obtained by mixing at least one of sulfuric acid, oxalic acid and phosphoric acid at a concentration of 0.1 to 50% by mass with the above-mentioned hydrochloric acid electrolytic solution.

[Coating film removal process]
The film removal step is a step of chemical dissolution treatment to remove the aluminum hydroxide film.
In the film removing step, for example, the aluminum hydroxide film can be removed by performing an acid etching treatment or an alkali etching treatment described later.

<Acid etching process>
The solution treatment is a treatment in which an aluminum hydroxide film is dissolved using a solution in which aluminum hydroxide is preferentially dissolved in preference to aluminum (hereinafter referred to as “aluminum hydroxide solution”).

  Here, as the aluminum hydroxide solution, for example, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid, chromium compound, zirconium compound, titanium compound, lithium salt, cerium salt, magnesium salt, sodium silicofluoride, fluoride fluoride An aqueous solution containing at least one selected from the group consisting of zinc, a manganese compound, a molybdenum compound, a magnesium compound, a barium compound and a halogen alone is preferred.

Specifically, as the chromium compound, for example, chromium (III) oxide, chromium (VI) anhydride and the like can be mentioned.
Examples of the zirconium-based compound include ammonium zirconium fluoride, zirconium fluoride and zirconium chloride.
Examples of titanium compounds include titanium oxide and titanium sulfide.
Examples of lithium salts include lithium fluoride and lithium chloride.
Examples of the cerium salt include cerium fluoride and cerium chloride.
As a magnesium salt, magnesium sulfide is mentioned, for example.
Examples of manganese compounds include sodium permanganate and calcium permanganate.
As a molybdenum compound, sodium molybdate is mentioned, for example.
As a magnesium compound, magnesium fluoride pentahydrate is mentioned, for example.
As a barium compound, for example, barium oxide, barium acetate, barium carbonate, barium chlorate, barium chloride, barium fluoride, barium iodide, barium lactate, barium oxalate, barium perchlorate, barium selenate, selenious acid Examples thereof include barium, barium stearate, barium sulfite, barium titanate, barium hydroxide, barium nitrate, and hydrates of these.
Among the above barium compounds, barium oxide, barium acetate and barium carbonate are preferred, and barium oxide is particularly preferred.
Examples of the halogen alone include chlorine, fluorine and bromine.

Among them, the above-mentioned aluminum hydroxide solution is preferably an aqueous solution containing an acid, and examples of the acid include nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid and the like, and even a mixture of two or more acids. Good.
The acid concentration is preferably 0.01 mol / L or more, more preferably 0.05 mol / L or more, and still more preferably 0.1 mol / L or more. The upper limit is not particularly limited, but generally 10 mol / L or less is preferable, and 5 mol / L or less is more preferable.

  The dissolution treatment is carried out by bringing the aluminum base on which the aluminum hydroxide film is formed into contact with the above-mentioned solution. The method for contacting is not particularly limited, and examples thereof include a dipping method and a spraying method. Among them, the immersion method is preferred.

The immersion method is a process of immersing the aluminum base on which the aluminum hydroxide film is formed in the above-described solution. Stirring during the immersion treatment is preferable because the treatment without unevenness is performed.
The immersion treatment time is preferably 10 minutes or more, more preferably 1 hour or more, and still more preferably 3 hours or more and 5 hours or more.

<Alkali etching process>
The alkali etching treatment is a treatment in which the surface layer is dissolved by bringing the aluminum hydroxide film into contact with an alkali solution.

  Examples of the alkali used for the alkali solution include caustic alkali and alkali metal salts. Specifically, examples of caustic alkali include sodium hydroxide (caustic soda) and caustic potash. Moreover, as an alkali metal salt, for example, alkali metal silicates such as sodium metasilicate, sodium silicate, potassium metasilicate and potassium silicate; sodium carbonate and alkali metal carbonates such as potassium carbonate; Alkali metal aluminates such as sodium acid and potassium aluminate; Alkali metal aldonates such as sodium gluconate and potassium gluconate; dibasic sodium phosphate, dibasic potassium phosphate and tribasic sodium phosphate And alkali metal hydrogen phosphates such as potassium triphosphate. Among them, a solution of caustic alkali and a solution containing both caustic alkali and an alkali metal aluminate are preferable from the viewpoint of high etching rate and low cost. In particular, an aqueous solution of sodium hydroxide is preferred.

  The concentration of the alkaline solution is preferably 0.1 to 50% by mass, and more preferably 0.2 to 10% by mass. When the aluminum ion is dissolved in the alkaline solution, the concentration of the aluminum ion is preferably 0.01 to 10% by mass, and more preferably 0.1 to 3% by mass. The temperature of the alkaline solution is preferably 10 to 90 ° C. The treatment time is preferably 1 to 120 seconds.

  As a method of bringing an aluminum hydroxide film into contact with an alkaline solution, for example, a method of passing an aluminum base on which an aluminum hydroxide film is formed through a tank containing an alkaline solution, aluminum on which an aluminum hydroxide film is formed There is a method of immersing the substrate in a bath containing an alkaline solution, and a method of spraying the alkaline solution onto the surface (aluminum hydroxide film) of the aluminum substrate on which the aluminum hydroxide film is formed.

Roughening treatment process
In the present invention, an optional roughening treatment step which may be possessed by the method for producing a sheet member is electrochemical roughening treatment (hereinafter referred to as “electrolytic roughening treatment”) on the aluminum substrate from which the aluminum hydroxide film has been removed. Roughening treatment (abbreviated as “roughening treatment”) to roughen the surface or the back surface of the aluminum substrate.
In the above embodiment, although the through-hole is roughened after forming the through-hole, the present invention is not limited to this, and the through-hole may be formed after the roughening.

In the present invention, the surface can be easily roughened by electrochemical graining treatment (hereinafter also referred to as “nitric acid electrolysis”) using an electrolyte mainly composed of nitric acid.
Alternatively, the surface can be roughened also by electrochemical surface roughening treatment (hereinafter also abbreviated as "hydrochloric acid electrolysis") using an electrolyte mainly composed of hydrochloric acid.

[Metal coating process]
In the present invention, the sheet member manufacturing method can adjust at least the penetration after the film removing step described above because the average opening diameter of the through holes formed by the above-described electrolytic dissolution treatment can be adjusted to a small range of about 1 μm to 20 μm. It is preferable to have a metallizing step of covering a part or all of the surface of the aluminum substrate including the inner wall of the hole with a metal other than aluminum.
Here, "covering a part or all of the surface of the aluminum substrate including at least the inner wall of the through hole with metal other than aluminum" means that at least the entire surface of the aluminum substrate including the inner wall of the through hole is penetrated The inner wall of the hole is meant to be coated, and the surfaces other than the inner wall may be uncoated or may be partially or entirely coated.

  In the metal-coating step, for example, a substitution treatment and a plating treatment described later are performed on an aluminum substrate having through holes.

<Replacement process>
The above-mentioned substitution treatment is a treatment in which zinc or a zinc alloy is substitutionally plated on part or all of the surface of the aluminum substrate including at least the inner wall of the through hole.
Examples of the displacement plating solution include a mixed solution of sodium hydroxide 120 g / L, zinc oxide 20 g / L, crystalline ferric chloride 2 g / L, rossell salt 50 g / L, and sodium nitrate 1 g / L.
Alternatively, a commercially available Zn or Zn alloy plating solution may be used, for example, Substar Zn-1, Zn-2, Zn-3, Zn-8, Zn-10, Zn-111 manufactured by Okuno Pharmaceutical Industry Co., Ltd. , Zn-222, Zn-291, etc. can be used.
The immersion time of the aluminum base in such a displacement plating solution is preferably 15 seconds to 40 seconds, and the immersion temperature is preferably 20 to 50 ° C.

<Plating treatment>
When zinc or a zinc alloy is displacement-plated on the surface of an aluminum substrate to form a zinc film by the above-described substitution treatment, for example, after the zinc film is replaced with nickel by electroless plating to be described later, It is preferable to apply a plating treatment to deposit various metals by electrolytic plating.

(Electroless plating process)
Commercially available products can be widely used as the nickel plating solution used for the electroless plating treatment, and examples thereof include an aqueous solution containing 30 g / L of nickel sulfate, 20 g / L of sodium hypophosphite, and 50 g / L of ammonium citrate.
Moreover, as a nickel alloy plating solution, the Ni-P alloy plating solution in which a phosphorus compound becomes a reducing agent, the Ni-B plating solution in which a boron compound becomes a reducing agent, etc. are mentioned.
The immersion time in such a nickel plating solution or nickel alloy plating solution is preferably 15 seconds to 10 minutes, and the immersion temperature is preferably 30 ° C to 90 ° C.

(Electrolytic plating process)
As the electrolytic plating process, for example, in the case of electroplating Cu, a plating solution containing 60 to 110 g / L of sulfuric acid, 160 to 200 g / L of sulfuric acid and 0.1 to 0.15 mL / L of hydrochloric acid is added to pure water, In addition, plating with Okuno Pharmaceutical Co., Ltd. TOP LUTINA SF base WR 1.5 to 5.0 mL / L, TOP LUTINA SF-B 0.5 to 2.0 mL / L and TOP LUTINA SF leveler 3.0 to 10 mL / L as additives. Liquid is mentioned.
The immersion time in such a copper plating solution is not particularly limited because it depends on the thickness of the Cu film, but for example, in the case of applying a 2 μm Cu film, it is preferable to immerse for about 5 minutes at a current density of 2 A / dm, The immersion temperature is preferably 20 ° C to 30 ° C.

[Water washing treatment]
In the present invention, it is preferable to wash with water after completion of the above-described processing steps. Pure water, well water, tap water or the like can be used for washing. A nip device may be used to prevent the processing solution from being carried into the next process.

The production of such a sheet member may be carried out using a cut sheet-like aluminum substrate, or may be carried out by roll-to-roll (hereinafter also referred to as Roll to Roll, also referred to as RtoR).
As well known, with RtoR, raw materials are drawn from a roll formed by winding a long raw material, and while being transported in the longitudinal direction, various treatments such as surface treatment are performed, and the treated raw materials are again treated. , A roll-shaped manufacturing method.
According to the manufacturing method of forming the through holes in the aluminum base as described above, the through holes of about 20 μm can be easily and efficiently formed by RtoR.

The method of forming the through holes is not limited to the method described above, and may be performed by a known method according to the forming material of the sheet member and the like.
For example, in the case of using a resin film such as a PET film as the sheet member, the through hole may be formed by a processing method such as laser processing that absorbs energy, or a machining method by physical contact such as punching or needle processing. it can.

[Frame]
The frame 16 is a member having a plurality of holes 17 and disposed in contact with one surface of the sheet member 12 to support the sheet member 12.

The opening diameter of the hole portion of the frame is preferably larger than the opening diameter of the through hole of the sheet member. In addition, the opening ratio of the hole portion of the frame is preferably larger than the opening ratio of the through hole of the sheet member.
Thereby, it is possible to prevent the sound absorbing effect of the fine through holes of the sheet member from being hindered while properly supporting the thin sheet member.

Moreover, it is preferable that the resonant vibration frequency of the sheet member in contact with the frame is larger than the audible range.
A thin sheet member is likely to cause resonant vibration of the sheet member with respect to sound waves. As a result, there arises a problem that the sound absorption characteristic is degraded in the frequency band around the resonant vibration frequency.
On the other hand, the rigidity of a sheet member is raised with a frame by arranging in a sheet member the frame which has two or more holes of a large opening diameter in contact. At that time, the resonant vibration frequency of the sheet member is made higher than the audible range by setting the aperture diameter of the hole portion of the frame so that the resonant vibration frequency of the sheet member becomes higher than the audible range. Thereby, in the audible range, it is possible to suppress the decrease in absorptivity due to the resonance vibration.

According to the study of the present inventors, since there is a sheet member and a through hole, it is considered that the sound passes through either of the two types. The path (path) passing through the sheet member is a path through which the solid vibration once converted to the membrane vibration of the sheet member is re-radiated as a sound wave, and the path passing through the through hole is a gas propagation sound in the through hole It is a path that passes directly as The path passing through the through-hole is considered to be dominant as the absorption mechanism of this time, but the sound in the frequency band near the resonant vibration frequency (first natural vibration frequency) of the sheet member is mainly of the sheet member. It is considered to pass through a path reradiated by membrane vibration.
On the other hand, the apparent rigidity of the sheet member can be enhanced by arranging the frame in contact with the sheet member, and the resonant vibration frequency can be made higher than the audible range. Therefore, since the sound in the audible range mainly passes through the path passing through the through hole rather than the path reradiated by the membrane vibration of the sheet member, the sound is absorbed by the friction when passing through the through hole.

The first natural vibration frequency of the sheet member disposed in contact with the frame 16 is the frequency of the natural vibration mode in which the sound wave is largely transmitted at the frequency where the sound wave shakes the membrane vibration most by the resonance phenomenon. In the present invention, since the first natural vibration frequency is determined by the structure of the frame and the sheet member, the inventors of the present invention have approximately the same value regardless of the presence or absence of the through hole perforated in the sheet member. Is found by
Also, at frequencies near the first natural vibration frequency, the film vibration becomes large, so the sound absorption effect due to the friction with the fine through holes becomes small.

  In the present invention, the audible range is 100 Hz to 20000 Hz.

Here, the frame may be disposed on one side of the sheet member, or may be disposed on both sides.
By arranging the frame on each of both sides of the sheet member, the rigidity of the sheet member can be made higher, and the resonance vibration frequency can be made higher. Therefore, the resonant vibration frequency of the sheet member can be easily made higher than the audible range.

  The shape of the opening cross section of the hole of the frame is not particularly limited, and, for example, other quadrangles such as rectangle, rhombus and parallelogram, triangles such as equilateral triangle, isosceles triangle and right triangle, equilateral triangle and pentagon The shape may be any shape such as a polygon including a regular polygon such as a regular hexagon, a circle, and an ellipse, or may be an irregular shape. Among them, the shape of the opening cross section of the hole is preferably a regular hexagon, and the frame preferably has a so-called honeycomb structure in which a plurality of holes having a regular hexagonal cross section are arranged closest to each other. By making the frame body have a honeycomb structure, the apparent rigidity of the sheet member 12 can be made higher, and the resonance vibration frequency can be easily made higher than the audible range.

The opening diameter of the hole suitably increases the rigidity of the sheet member, the opening diameter is larger than the through hole of the sheet member, the point to reduce the influence on the path passing through the through hole, and the handling etc. From the viewpoint of preventing direct contact with the sheet member, the opening diameter of the hole portion of the frame is preferably 22 mm or less, more preferably 0.1 mm or more and 15 mm or less, and 1 mm or more Particularly preferred is 10 mm or less.
In addition, the opening diameter of a hole measured the area of a hole part, respectively, and was taken as the diameter (circle equivalent diameter) when replacing with the circle used as the same area.

  The two frames disposed on both sides of the sheet member may have the same configuration or may be different. For example, in the two frames, the opening diameter of the hole, the opening ratio, the material, and the like may be the same or may be different from each other.

Further, although the sheet member and the frame may be disposed in contact with each other, it is preferable that they be adhered and fixed.
By adhesively fixing the sheet member and the frame, the rigidity of the sheet member can be made higher, and the resonance vibration frequency can be made higher. Therefore, the resonant vibration frequency of the sheet member can be easily made higher than the audible range.

  The adhesive used to bond and fix the sheet member and the frame may be selected according to the material of the sheet member, the material of the frame, and the like. As the adhesive, for example, an epoxy-based adhesive (Araldite (registered trademark) (manufactured by Nichiban Co., Ltd.), etc.), a cyanoacrylate-based adhesive (Aron Alpha (registered trademark) (manufactured by Toagosei Co., Ltd., etc.), acrylic A system adhesive etc. can be mentioned.

The light guide member further includes a second frame having one or more openings, and a laminate of the sheet member and the frame is disposed to cover the openings of the second frame. It is also good.
The opening diameter of the opening of the second frame is larger than the opening diameter of the opening of the frame, and the opening ratio of the opening of the second frame is higher than the opening ratio of the opening of the frame large.
As described above, by further including the second frame, the rigidity of the sheet member can be made higher, and the resonance vibration frequency can be made higher. Therefore, the resonant vibration frequency of the sheet member can be easily made higher than the audible range.

The physical properties or characteristics of the structural member that can be combined with the soundproof member having the light guide structure of the present invention will be described below.
[Flame retardance]
In the case of using the soundproof member having the light guide structure of the present invention as a soundproofing material in construction materials and equipment, it is required to be flame retardant.
Therefore, the sheet member is preferably flame retardant. When a resin is used as the sheet member, for example, Lumira (registered trademark) non-halogen flame retardant type ZV series (made by Toray Industries, Inc.), which is a flame retardant PET film, Teizine Tetron (registered trademark) UF (manufactured by Teijin Limited) And / or Dairamie (registered trademark) (manufactured by Mitsubishi Plastics Co., Ltd.) which is a flame retardant polyester film may be used.
The flame retardance can also be imparted by using metal materials such as aluminum, nickel, tungsten and copper.

[Heat-resistant]
Since there is a concern that the soundproofing characteristics may change due to the expansion and contraction of the structural member of the light guide structure of the present invention with the environmental temperature change, the material constituting this structural member is preferably heat resistant, particularly low thermal contraction. .
When a resin is used as the sheet member, for example, Teijin Tetron (registered trademark) film SLA (manufactured by Teijin DuPont Film Co., Ltd.), PEN film Teonex (registered trademark) (manufactured by Teijin DuPont Film Co., Ltd.), and / or Lumirror (registered trademark) It is preferable to use an off annealing low shrinkage type (manufactured by Toray Industries, Inc.) or the like. It is also preferable to use a metal film such as aluminum having a thermal expansion coefficient smaller than that of a plastic material.

[Weather resistance / light resistance]
When the soundproof member having the light guide structure of the present invention is disposed outdoors or in a place where light is to be emitted, the heat resistance of the structural member becomes a problem.
Therefore, when using a resin as a sheet member, special polyolefin film (Artply (registered trademark) (Mitsubishi Resin Co., Ltd.)), acrylic resin film (Acriprene (Mitsubishi Rayon Co., Ltd.)), and / or scotchcal It is preferable to use a weather-resistant film such as Film (trademark) (manufactured by 3M).
In addition, light resistance to ultraviolet light and the like can be provided by using a metal material such as aluminum.
With regard to moisture resistance, it is preferable to appropriately select a sheet member having high moisture resistance. It is preferable to select a sheet member appropriately also with respect to water absorbency and chemical resistance.

[garbage]
In long-term use, dust may adhere to the surface of the sheet member, which may affect the soundproofing properties of the light guide structure of the present invention. Therefore, it is preferable to prevent the adhesion of dust or remove the adhered dust.
As a method of preventing dust, it is preferable to use a sheet member made of a material to which dust does not easily adhere. For example, by using a conductive film (Fleclear (registered trademark) (made by TDK Corporation) and / or NCF (made by Nagaoka Sangyo Co., Ltd.), etc., the sheet member is not charged, so adhesion of dust due to charging is It can prevent. Further, by selecting a sheet member in which the sheet member itself has conductivity like a metal material such as aluminum, it is possible to prevent the adhesion of dust due to static electricity.
In addition, a fluorine resin film (Dinoc film (trademark) (manufactured by 3M)) and / or a hydrophilic film (Miraclean (manufactured by Lifeguard Co., Ltd.), RIVEX (manufactured by Riken Technos Co., Ltd.), and / or SH2CLHF (3M company) It is also possible to suppress the adhesion of dust by using the Furthermore, the stain of the sheet member can also be prevented by using a photocatalyst film (Laclean (manufactured by Kimoto Co., Ltd.)). The same effect can be obtained by applying a spray having the conductivity, hydrophilicity, and / or photocatalytic property and / or a spray containing a fluorine compound to the sheet member.
In addition, by forming a hydrophilic surface including the inside of pores by silica coating, making it a hydrophobic surface by fluorine coating, and simultaneously using them simultaneously, both hydrophilic soil and hydrophobic soil are easily peeled off. It can be antifouling coated.

In addition to using special materials as described above, it is also possible to prevent contamination by providing a cover on the sheet member. As the cover, use a thin film material (such as Saran wrap (registered trademark)), a mesh (made of metal, plastic, etc.) having a mesh size that does not pass dust, non-woven fabric, urethane, airgel, porous film, etc. Can.
Moreover, when using especially thin film material etc. as a cover, in order not to inhibit the effect of the through-hole of this invention, it is preferable not to stick to the sheet member 12, but to leave distance. In addition, since thin film material is fixed in a stretched state in order to allow sound to pass without strong film vibration, it is desirable that the thin film material be loosely supported because film vibration is likely to occur.
As a method of removing the attached dust, it is possible to remove the dust by radiating a sound to the sheet member and strongly vibrating the sheet member. Also, the same effect can be obtained by using a blower or wiping.

[Wind pressure]
When the strong wind hits the sheet member, the sheet member is pushed, and the resonance frequency may change. Therefore, the influence of wind can be suppressed by covering with a nonwoven fabric, urethane, and / or a film etc. on a sheet member.

The light guide structure of the present invention is not limited to the one disposed and used in the duct member of the above-mentioned building.
For example, you may use for the cage for pet breeding. By installing the light guiding structure of the present invention in a pet rearing cage, for example, by connecting the outside and the inside of the pet cage, it is possible to provide a light transmitting sound guiding pet cage that guides light into the pet cage. By using this cage, it is possible to protect pets in the cage from external noise, and to suppress the rattling of pets in the cage from leaking out.

  Hereinafter, the present invention will be described in more detail based on examples. The materials, amounts used, proportions, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Accordingly, the scope of the present invention should not be construed as limited by the following examples.

Example 1
<Production of light guide member>
The process shown below was given to the surface of an aluminum base (JIS H-4160, alloy number: 1N30-H, aluminum purity: 99.30%) of average thickness 20 micrometers, and the light guide member 10 was produced.

(A1) Aluminum hydroxide film formation treatment (film formation process)
With the use of an electrolytic solution kept at 50 ° C. (nitric acid concentration: 10 g / L, sulfuric acid concentration: 6 g / L, aluminum concentration: 4.5 g / L, flow rate: 0.3 m / s), the above aluminum base material is used as a cathode An electrolytic treatment was applied for 20 seconds under the condition of 1000 C / dm ² to form an aluminum hydroxide film on the aluminum substrate. In addition, the electrolysis process was performed by direct-current power supply. The current density was 50 A / dm ² .
After the formation of the aluminum hydroxide film, washing with water by spraying was performed.

(B1) Electrolytic dissolution treatment (through hole forming step)
Next, using the electrolytic solution (nitric acid concentration 10 g / L, sulfuric acid concentration 6 g / L, aluminum concentration 4.5 g / L, flow rate 0.3 m / s) kept at 50 ° C., the aluminum base material is used as the anode and the electric quantity The electrolytic treatment was performed for 24 seconds under the condition of the total sum of 600 C / dm ² to form through holes in the aluminum base and the aluminum hydroxide film. In addition, the electrolysis process was performed by direct-current power supply. The current density was 25 A / dm ² .
After the formation of the through holes, the plate was rinsed with a spray and dried.

(C1) Removal treatment of aluminum hydroxide film (coating removal process)
Next, the aluminum base after electrolytic dissolution treatment is immersed in an aqueous solution (sodium hydroxide concentration 50 g / L, aluminum ion concentration 3 g / L) (liquid temperature 35 ° C.) for 32 seconds, and then nitric acid concentration 10 g / L, aluminum The aluminum hydroxide film was dissolved and removed by immersing in an aqueous solution having an ion concentration of 4.5 g / L (liquid temperature: 50 ° C.) for 40 seconds.
Thereafter, the sheet was washed with water by spraying and dried to prepare a sheet member (light guide member) having a through hole.
When the average aperture diameter and the average aperture ratio of the through holes of the manufactured light guide member 10 were measured, the average aperture diameter was 24.4 μm, and the average aperture ratio was 5.6%.
Moreover, it was 88% when the light reflectivity in the visible light area | region of the light guide member 10 was measured.

<Production of duct member>
As shown in FIG. 14, as a duct member 16, the inner diameter D ₁ = 100 mm, a length L ₁ = 100 mm of the portion, the inner diameter D ₂ = 120 mm, length L ₂ = 600 mm sections, the inner diameter D ₁ = 100 mm, the length L ₁ = 100 mm portion was produced a duct member having a connection structure in the forward axial direction. The material of the duct member was acrylic.
In the following description, it refers to a portion of the inner diameter D ₁ diameter portion, also a portion of the inner diameter D ₂ large-diameter portion.

<Production of light guide structure>
The light guide member 10 was formed in a cylindrical shape so as to have a diameter of 100 mm. The length is 800 mm. The light guide member 10 formed in a cylindrical shape was inserted into the duct member 16, and the portion disposed in the small diameter portion was attached to the inside of the small diameter portion. Thereby, as shown in FIG. 14, the light guide member 10 is installed inside the duct member 16, and a space is formed between the light guide member 10 and the duct member 16 in the large diameter portion of the duct member 16. A light guide structure 100a was produced.

Example 2
Example 1 is the same as Example 1 except that an annular member 18 having an outer diameter of 120 mm, an inner diameter of 100 mm, and an inner diameter of 100 mm is attached to the large diameter portion of the duct member 16 of Example 1 every 50 mm in the axial direction. The light guide structure was produced similarly (refer FIG. 15).
That is, in the light guide structure of the second embodiment, twelve cells of 30 mm in length are formed.
FIGS. 15 to 18 show half cross sections of the light guide structure.

[Example 3]
Example 1 is the same as Example 1 except that an annular member 18 having an outer diameter of 120 mm, an inner diameter of 100 mm, and a thickness of 20 mm is attached to the large diameter portion of the duct member 16 of Example 1 every 100 mm in the axial direction. Similarly, a light guide structure was produced (see FIG. 16).
That is, in the light guide structure of the third embodiment, six cells of 80 mm in length are formed.

Example 4
Example 1 is the same as Example 1 except that an annular member 18 having an outer diameter of 120 mm, an inner diameter of 100 mm, and an inner diameter of 100 mm is attached to the large diameter portion of the duct member 16 of Example 1 every 200 mm in the axial direction. Similarly, a light guide structure was produced (see FIG. 17).
That is, in the light guide structure of the fourth embodiment, three cells of 180 mm in length are formed.

[Example 5]
An annular partition member 18 having an outer diameter of 120 mm, an inner diameter of 100 mm, and a thickness of 20 mm was attached to the large diameter portion of the duct member 16 of Example 1 so that the cell size was 100 mm, 180 mm, 280 mm. A light guide structure was produced in the same manner as in Example 1 except for the above (see FIG. 18).

Comparative Example 1
A light guide structure was produced in the same manner as in Example 1 except that the sheet member was not provided. That is, it was set as a duct member single-piece.

[Evaluation]
<Soundproof performance>
A microphone is placed in each of the two small diameter parts of the light guide structure produced, and a sound source (speaker) is placed on one end face of the light guide structure, and the transmissivity and absorptivity in the range of 100 Hz to 4000 Hz The rate of absorption (rate of absorption) was measured to evaluate the soundproofing performance.
The measurement result of the transmittance | permeability of Examples 1-3 is shown in FIG. The measurement result of the absorptivity of Examples 1-3 is shown in FIG. The measurement result of the transmittance | permeability of Example 1 and the comparative example 1 is shown in FIG. The measurement result of the transmittance | permeability of Example 4 and Example 5 is shown in FIG. The measurement result of the absorptivity of Example 4 and Example 5 is shown in FIG.

  As can be seen from FIG. 21, it can be seen that the transmittance of Example 1 is lower than that of Comparative Example 1. In particular, while the transmittance in Example 1 is smaller on the high frequency side, the transmittance in Comparative Example 1 is large even on the high frequency side.

Further, as can be seen from FIG. 19 and FIG. 20, the transmittances of Example 2 and Example 3 are smaller than that of Example 1, and the absorptivity is larger.
Moreover, in Example 1, it became a graph which the transmittance | permeability vibrates large with respect to the frequency. This is because the acoustic impedance of the duct changes at the position where the thickness of the duct member changes, so the length direction between the two portions where the thickness changes changes like a resonator, and the resonance transmission phenomenon It is because it occurs.
On the other hand, in the second and third embodiments, the vibration is largely suppressed. This is considered to be due to the fact that the resonator is divided into a plurality of resonators by inserting the partitions, and the resonance frequency is also shifted to the high frequency side, thereby reducing the influence on the audible area.

  From FIGS. 22 and 23, it can be seen that the vibration of the transmittance and the absorptivity is smaller and the transmittance itself is smaller and the absorptivity is larger as compared with the fourth embodiment. The fourth embodiment and the fifth embodiment have the same number of cells, but the fourth embodiment has the same cell size, whereas the fifth embodiment has the same cell size. By making the sizes of the cells different, the resonant frequencies corresponding to the respective cells become different. Therefore, the vibration of the transmittance and the absorptivity is smaller in Example 5 in which the cell size is different than in Example 4 in which the size of all the cells is the same.

<Light guiding performance>
For the evaluation of the light guiding performance, the amount of light passing through the duct member was evaluated using LS-150 manufactured by Konica Minolta as a luminance meter. Ushio Electric's xenon short arc lamp was used as a white light source. First, the light source was disposed at a distance of 10 cm from one end face of the duct member.
First, a luminance meter was placed at the end of the duct on the light source side, and the light quantity of the duct end on the light source side was measured to obtain the incident light quantity. Next, a luminance meter was placed at the end of the exit side of the duct (opposite to the light source side), and the light quantity of the duct end at the exit side was measured to obtain the quantity of emitted light. The emitted light quantity / incident light quantity was determined and evaluated as the light guiding efficiency.

  In any of the examples 1 to 5, the light guiding efficiency was over 90%. On the other hand, Comparative Example 1 was an acrylic duct with a low reflectance, so that it was 10% light guiding performance with no light guiding other than the directly reaching light.

  Next, light guide performance in the case where the duct member has a bent portion was examined. In the case of having a bent portion, the light guiding performance is required more than in the case of the straight shape.

[Example 6]
As shown in FIG. 25, a light guide structure curved with a constant radius of curvature was produced.
The duct member 16 is made of aluminum, and has a sectional shape of 40 mm × 40 mm, a length of about 950 mm, and a curvature radius of 600 mm.
The sheet member 10 is disposed at the bent portion of the duct member 16 via the partition member 18.
The sheet member 10 was the same as the sheet member 10 produced in Example 1.
The partition member 18 was disposed such that the size of the space (cell) between the sheet member 10 and the duct member 16 was 10 mm in thickness, 100 mm in length, and 40 mm in width.

[Evaluation]
<Soundproof performance>
The arrangement of the sheet members was changed so that the number of cells was 1 to 5, and the sound transmittance and absorptivity were measured in the same manner as in Example 1. Moreover, also when not arrange | positioning a sheet member, it measured as a comparative example.
The measurement result of the transmittance is shown in FIG. 26, and the measurement result of the absorptivity is shown in FIG.

  As shown in FIGS. 26 and 27, it can be seen that the larger the number of cells, that is, the larger the ratio of the sheet member 10 in the duct member, the lower the transmittance and the higher the sound absorption coefficient.

<Light guiding performance>
Further, the arrangement of the sheet members was changed so that the number of cells was 1 to 5, and the light transmittance was measured in the same manner as in Example 1.
The light guiding efficiency was about 70% because there was substantially no change because the material of the duct and the material of the sheet member were both aluminum.

[Example 7]
As shown in FIG. 28, a light guide structure having a bent portion bent in an L shape was produced.
The duct member 16 is made of aluminum: sectional shape 40 mm × 40 mm, length 600 mm on the sound incident side, and length 600 mm on the sound radiation side.
The sheet member 10 is disposed at the bent portion of the duct member 16 via the partition member 18. As shown in FIG. 28, the sheet member 10 was disposed at the bending portion so that the surface was orthogonal to the longitudinal direction of the duct member on the incident side.
The sheet member 10 was the same as the sheet member 10 produced in Example 1.
The partition member 18 was disposed such that the size of the space (cell) between the sheet member 10 and the duct member 16 was 10 mm in thickness, 40 mm in length, and 40 mm in width.
When two or more cells are arranged, as shown in FIG. 29, the sheet members 10 are arranged in the longitudinal direction of the duct member on the output side.

[Evaluation]
<Soundproof performance>
The arrangement of the sheet members was changed so that the number of cells was 1, 3, 6, 9, 12 and the sound transmittance and absorptivity were measured in the same manner as in Example 1. Moreover, also when not arrange | positioning a sheet member, it measured as a comparative example.
The measurement result of the transmittance is shown in FIG. 30, and the measurement result of the absorptivity is shown in FIG.

  As shown in FIG. 30 and FIG. 31, it can be seen that, as the number of cells increases, the transmittance decreases and the sound absorption coefficient increases.

<Light guiding performance>
Further, the arrangement of the sheet members was changed so that the number of cells was 1, 3, 6, 9, 12 and the light transmittance was measured in the same manner as in Example 1.
The light guiding efficiency was about 40% because there was substantially no change because the material of the duct and the material of the sheet member were both aluminum.

[Example 8]
As shown in FIG. 32, the sheet member 10 was obliquely disposed at the bent portion of the L-shaped duct member similar to that of the seventh embodiment to fabricate a light guide structure. That is, the surface was inclined 45 degrees with respect to the longitudinal direction of the duct member on the incident side and the longitudinal direction of the duct member on the outgoing side.

[Evaluation]
<Soundproof performance>
The sound transmittance and absorptivity were measured in the same manner as in Example 1. Moreover, also when the sheet | seat member was not arrange | positioned, it measured as the comparative example 8. FIG.
FIG. 33 shows the measurement results of transmittance, and FIG. 34 shows the measurement results of absorptivity.

  As shown in FIGS. 33 and 34, it can be seen that the example has a low transmittance and a high sound absorption coefficient as compared with the comparative example.

<Light guiding performance>
Also, the light transmittance was measured in the same manner as in Example 1.
By making the angle at the right angle of the L-shaped part shallow, the light guiding efficiency also increases. The light guiding efficiency was 60%.

[Example 9]
As shown in FIG. 35, a light guide structure was produced in which the sheet member 10 of Example 8 was curved in an arc shape. Specifically, the sheet member 10 was curved at a radius of curvature of 40 mm.

[Evaluation]
<Soundproof performance>
The sound transmittance and absorptivity were measured in the same manner as in Example 1. Moreover, also when not arrange | positioning a sheet member, it measured as the comparative example 9. FIG.
The measurement result of the transmittance is shown in FIG. 36, and the measurement result of the absorptivity is shown in FIG.

  As shown in FIGS. 36 and 37, it can be seen that the example has a low transmittance and a high sound absorption coefficient as compared with the comparative example.

<Light guiding performance>
Also, the light transmittance was measured in the same manner as in Example 1.
By making the L-shaped part at right angles circular, the light guiding efficiency also increases. The light guiding efficiency was 70%.

[Simulation 1]
Next, the optimum average aperture ratio to the average aperture diameter of the through holes was examined by simulation.
The simulation was implemented on the acoustic module of the finite element method calculation software COMSOL ver 5.2a (COMSOL Corporation). The sheet member having fine through holes was modeled according to Maa's equation. Dah-You Maa. The Journal of the Acoustical Society of America 104, 2861 (1998), etc. and the thickness of the sheet member, the through-hole, and the like. It is an equation for obtaining the complex acoustic impedance of the sheet member from the average aperture diameter and the average aperture ratio. This makes it possible to mathematically model and handle the sheet member having a large number of fine through holes.

  Calculations in the case where the average opening diameter is 100 μm or less were performed in detail at an optimum average opening ratio with respect to the average opening diameter of the through holes. The results of showing the optimum average opening ratio for each average opening diameter of the through holes for each of the thicknesses 10 μm, 20 μm, 30 μm, 50 μm and 70 μm are shown in a double logarithm graph in FIG. From the graph of FIG. 38, it was found that the optimum average aperture ratio changes by approximately -1.6 power to the average aperture diameter of the through holes.

More specifically, when the optimum average aperture ratio is rho_center, the average aperture diameter of the through holes is phi (μm), and the thickness of the sheet member is t (μm), the double logarithm graph of FIG. 38 is approximated by a power function The optimal average aperture ratio rho_center is
rho_center = a × phi ^-1.6
It became clear that it was determined by a = 2 + 0.25 x t.
In this way, particularly when the average opening diameter of the through holes is small, the absorptance does not increase as the average opening ratio decreases, and the optimum average opening ratio is the thickness of the sheet member and the average opening diameter of the through holes. Revealed to be determined by The optimal average aperture ratio increases as the thickness of the sheet member increases, and decreases as the average aperture diameter increases.

As described above, the range in which the absorptance increases is gradually spread around the optimum average aperture ratio. For this detailed analysis, the results of changing the average aperture ratio in a simulation of a 50 μm thick sheet member are shown in FIG. The average opening diameter of the through holes was 10 μm, 15 μm, 20 μm, 30 μm and 40 μm, and the average opening ratio was changed from 0.5% to 99%.
For any average aperture diameter, the range of the average aperture ratio where the absorptance is large extends around the optimum average aperture ratio. As a feature, the range of the average aperture ratio, in which the absorptivity becomes larger as the average aperture diameter of the through holes is smaller, is wider. In addition, the range over which the absorptivity is larger is wider on the average aperture ratio side higher than the optimal average aperture ratio.

  In the range of the average opening diameter of 1 μm or more and less than 100 μm, the maximum value of the absorption is approximately 50% at any average opening diameter, so the lower opening ratio at which the absorption becomes 30%, 40%, 45% The upper aperture ratio is shown in Table 1, respectively. In addition, the range of each absorptivity from the optimum average aperture ratio is shown in Table 2.

  For example, when the average opening diameter of the through holes is 20 μm, the optimum average opening ratio is 11%, and the lower limit is 4.5% and the upper limit is 28%. At this time, the range of the average opening ratio at which the absorptance is 40% based on the optimum average opening ratio is (4.5% -11.0%) =-6.5% to (28.0% -11.0%) = 17.0%. In Table 2, it showed as -6.5%-17.0%.

From Table 2, when the width of the absorptivity for each average opening diameter of the through holes is compared, assuming that the average opening diameter of the through holes is phi (μm), the width of the absorptivity at a ratio of approximately 100 × phi ^-2 Changes. Therefore, an appropriate range can be determined for each average opening diameter for each of the absorption rates of 30%, 40%, and 45%.

That is, the range of the absorptance of 30% uses the above-mentioned optimum average aperture ratio rho_center and uses the range when the average aperture diameter of the through holes is 20 μm as a reference.
rho_center-0.085 × (phi / 20) ^-2
Is the lower limit average aperture ratio,
rho_center + 0.35 × (phi / 20) ^-2
It is necessary to be in the range where is the average aperture ratio of the upper limit. However, the average aperture ratio is limited to a range larger than 0 and smaller than 1 (100%).

Desirably, the absorption rate is in the range of 40%,
rho_center-0.24 × (phi / 10) ^-2
Is the lower limit average aperture ratio,
rho_center + 0.57 × (phi / 10) ^-2
It is desirable that the range is the upper limit average aperture ratio. Here, in order to reduce the error as much as possible, the reference of the average aperture diameter was 10 μm.

More preferably, the absorption rate is in the range of 45%,
rho_center-0.185 × (phi / 10) ^-2
Is the lower limit average aperture ratio,
rho_center + 0.34 × (phi / 10) ^-2
It is further desirable that the range of the upper limit of the average aperture ratio be.

Furthermore, in order to determine the range of the optimal average aperture ratio in the case of a smaller absorption rate, the average aperture ratio was finely calculated in the small range. As a representative example, FIG. 40 shows the result in the case where the thickness of the sheet member is 50 μm and the average opening diameter of the through holes is 30 μm.
Tables 3 and 4 show the range of the average aperture ratio as the absorptivity and the approximate expression for each of the absorptances of 10%, 15% and 20%. In Table 4, "rho_center" is described as "rc".

From Tables 3 and 4, the range of the absorption rate of 10% uses the above-mentioned optimum average aperture ratio rho_center, and uses the range when the average aperture diameter of the through holes is 30 μm as a reference.
rho_center-0.052 x (phi / 30) ^-2
Is the lower limit average aperture ratio,
rho_center + 0.795 × (phi / 30) ^-2
It is necessary to be in the range where is the average aperture ratio of the upper limit. However, the average aperture ratio is limited to a range larger than 0 and smaller than 1 (100%).

Desirably, the absorption rate is 15% or more, and the range is
rho_center-0.050 x (phi / 30) ^-2
Is the lower limit average aperture ratio,
rho_center + 0.505 × (phi / 30) ^-2
Is a range in which the upper limit of the average aperture ratio.

More desirably, the absorption rate is 20% or more, and the range is
rho_center-0.048 × (phi / 30) ^-2
Is the lower limit average aperture ratio,
rho_center + 0.345 × (phi / 30) ^-2
Is a range in which the upper limit of the average aperture ratio.

More desirably, the absorptivity is within the range of the average aperture ratio of 30% or more, 40% or more, or 45% or more, and the absorptivity can be further increased.
As mentioned above, the characteristics of the sound absorption phenomenon by the friction in the through-hole were clarified using simulation. Further, the size of the absorptivity was determined by the thickness of the sheet member, the average opening diameter of the through holes, and the average opening ratio, and the optimum value range was determined.
From the above, the effects of the present invention are clear.

DESCRIPTION OF SYMBOLS 10 Light guide member 11 Aluminum base 12 Sheet member 13 Aluminum hydroxide film 14 Through-hole 16 Duct member 18 Partition member 100a, 100b Light guide structure 102, 104 Opening 200 Building

Claims (17)

A sheet member having a plurality of through holes penetrating in the thickness direction,
The average opening diameter of the through holes is 1 μm or more and 250 μm or less,
At least one surface of the sheet member has a light reflectance of 50% or more in a visible light region,
Both sides of at least a portion of the sheet member are in contact with the fluid,
A light guide member in which the peak value of the normal incidence sound absorption coefficient of the sheet member is 10% or more in the audible range.   The light guide member according to claim 1, wherein the sheet member is formed in a tubular shape.   The light guide member according to claim 1, wherein an average opening diameter of the through holes is 1 μm or more and less than 100 μm. Assuming that the average opening diameter of the through holes is phi (μm) and the thickness of the sheet member is t (μm), the average opening ratio rho of the through holes is in a range larger than 0 and smaller than 1 and rho_center A range having an upper limit of rho_center + (0.795 × (phi / 30) ⁻² ) with a lower limit of rho_center− (0.052 × (phi / 30) ⁻² ) centering on (2 + 0.25 × t) × phi ^−1.6 The light guide member according to claim 3.   The light guide member according to any one of claims 1 to 4, wherein an average aperture ratio of the through holes is 20% or less.   The light guide member according to any one of claims 1 to 5, wherein the sheet member is made of a material having heat resistance and flame resistance.   The light guide member according to any one of claims 1 to 6, wherein a forming material of the sheet member is a metal.   The light guide member according to claim 7, wherein the metal is aluminum.   The light guide member according to any one of claims 1 to 8, wherein in the visible light region, the sheet member has a light reflectance different depending on a wavelength.   A light guide structure in which the light guide member according to any one of claims 1 to 9 is disposed in a tubular duct member.   The light guide structure according to claim 10, wherein the light guide member is disposed parallel to the inner wall surface of the duct member.   The light guide structure according to claim 11, further comprising: a partition member that divides a space between the light guide member and an inner wall surface of the duct member in an axial direction of the duct member.   The light guide structure according to claim 12, wherein when each space partitioned by the partition member is a cell, at least one cell having different sizes from one another is provided.   The light guide structure according to claim 12 or 13, wherein the visible light transmittance of the partition member is 60% or more. The duct member has a bent portion,
The light guide structure according to any one of claims 10 to 14, wherein the light guide member is disposed at the bent portion. One end of the duct member is disposed outside the building, and the other end of the duct member is disposed inside the building.
The light guide structure according to any one of claims 10 to 15, wherein light is guided from the outside to the inside of the building.   The light guide structure according to any one of claims 10 to 16, wherein the duct member is at least one of an intake pipe and an exhaust pipe.